A Novel Spatial Position Prediction Navigation System Makes Surgery More Accurate.

During intravascular interventional surgery, the 3D surgical navigation system can provide doctors with 3D spatial information of the vascular lumen, reducing the impact of missing dimension caused by digital subtraction angiography (DSA) guidance and further improving the success rate of surgeries. Nevertheless, this task often comes with the challenge of complex registration problems due to vessel deformation caused by respiratory motion and high requirements for the surgical environment because of the dependence on external electromagnetic sensors. This article proposes a novel 3D spatial predictive positioning navigation (SPPN) technique to predict the real-time tip position of surgical instruments. In the first stage, we propose a trajectory prediction algorithm integrated with instrumental morphological constraints to generate the initial trajectory. Then, a novel hybrid physical model is designed to estimate the trajectory's energy and mechanics. In the second stage, a point cloud clustering algorithm applies multi-information fusion to generate the maximum probability endpoint cloud. Then, an energy-weighted probability density function is introduced using statistical analysis to achieve the prediction of the 3D spatial location of instrument endpoints. Extensive experiments are conducted on 3D-printed human artery and vein models based on a high-precision electromagnetic tracking system. Experimental results demonstrate the outstanding performance of our method, reaching 98.2% of the achievement ratio and less than 3 mm of the average positioning accuracy. This work is the first 3D surgical navigation algorithm that entirely relies on vascular interventional robot sensors, effectively improving the accuracy of interventional surgery and making it more accessible for primary surgeons.

Chemical renal artery denervation with appropriate phenol in spontaneously hypertensive rats.

OBJECTIVE: To explore the effectiveness of renal denervation (RDN) on blood pressure with the appropriate dosage of phenol/ethanol solution in spontaneously hypertensive rats (SHRs). METHODS: RDN was performed on the bilateral renal artery. Forty SHRs were divided into four groups according on the dosage of phenol (10% phenol in absolute ethanol): sham group, 0.5 mL phenol group, 1 mL phenol group and 1.5 mL phenol group (n = 10 in each group). Blood pressure was measured by tail-cuff plethysmography. Plasma creatinine was determined four weeks after the treatment. The kidneys and renal arteries were collected and processed for histological examination. RESULTS: A sustained decrease in systolic blood pressure (SBP) was only observed after the application of 1 mL phenol for four weeks, while SBP was lowered during the first week after RDN and increased in the following three weeks in the 0.5 mL and 1.5 mL phenol groups compared with the sham group. Renal norepinephrine (NE) was significantly decreased four weeks after RDN in the 1 mL and 1.5 mL phenol group compared with the sham group, but not in the 0.5 ml group. RDN with 1 mL phenol obviously reduced glomerular fibrosis. Histopathological analysis showed that tyrosine hydroxylase immunoreactivity was lower in the 1 mL and 1.5 mL phenol groups compared with the sham group. Moderate renal artery damage occurred in the 1.5 mL phenol group. CONCLUSION: Chemical denervation with 1 ml phenol (10% phenol in absolute ethanol) effectively and safely damaged peripheral renal sympathetic nerves and contributed to the sustained reduction of blood pressure in SHRs.

Efficacy and safety of a novel multi-electrode radiofrequency ablation catheter for renal sympathetic denervation in pigs.

OBJECTIVE: To investigate the safety and efficacy of a self-developed novel multi-electrode radiofrequency ablation catheter (Spark) for catheter-based renal denervation (RDN). METHODS: A total of 14 experimental miniature pigs were randomly divided into four groups (55°& 5-watt, 55°& 8-watt, 65°& 5-watt, and 65° & 8-watt groups). Spark was used for left and right renal artery radiofrequency ablation. Blood samples collected from renal arteries and veins as well as renal arteriography were performed on all animals before, immediately after, and three months after procedure to evaluate the effects of Spark on the levels of plasma renin, aldosterone, angiotensin I, and angiotensin II as well as the pathological changes of renal arteries. RESULTS: One pig died of an anesthetic accident, 13 pigs successfully underwent the bilateral renal artery ablation. Compared with basic measurements, pigs in all the four groups had significantly decreased mean arterial pressure after procedure. Histopathological analysis showed that this procedure could result in intimal hyperplasia, significant peripheral sympathetic nerve damage in the renal arteries such as inflammatory cell infiltration and fibrosis in perineurium, uneven distribution of nerve fibers, tissue necrosis, severe vacuolization, fragmented and unclear nucleoli myelin degeneration, sparse axons, and interruption of continuity. In addition, the renal artery radiofrequency ablation could significantly reduce the levels of plasma renin, aldosterone, angiotensin I, and angiotensin II in pigs. CONCLUSIONS: The results suggest that this type of multi-electrode catheter-based radiofrequency ablation could effectively remove peripheral renal sympathetic nerves and reduce the activity of systemic renin-angiotensin system in pigs, thus facilitating the control of systemic blood pressure in pigs.

Clinical characteristics associated with high on-treatment platelet reactivity of patients undergoing PCI after a 300†mg loading dose of clopidogrel, measured by thrombelastography.

BACKGROUND: Dual antiplatelet therapy with clopidogrel and aspirin is the standard of care for patients undergoing percutaneous coronary intervention (PCI). OBJECTIVE: To determine the clinical characteristics associated with high on-treatment platelet reactivity (HPR) of patients undergoing PCI after a 300 mg loading dose of clopidogrel, measured by thrombelastography (TEG). METHODS AND RESULTS: 394 consecutive patients were enrolled in this prospective observational study. All had been receiving aspirin 100 mg/day for more than 7 days, but were clopidogrel naïve. A 300 mg loading dose of clopidogrel was given more than 12 h before the procedure. The cut-off point for HPR was defined as ≥70% adenosine-5-diphosphate-induced aggregation. The prevalence of HPR was 21% as measured by TEG. More women than men (41.7% vs 27.1%, p=0.01) were found in the HPR group. Raised glycosylated haemoglobin (HbA1c) was more prevalent in the HPR group than in the group with normal on-treatment platelet reactivity (NPR) (45.2% vs 30.0%, p=0.009). Patients with HPR had a higher level of total plasma cholesterol (4.8±1.5 mmol/l vs 4.3±1.1 mmol/l, p=0.002) and low-density lipoprotein cholesterol (2.8±1.1 mmol/l vs 2.5±0.9 mmol/l, p=0.022) than those with NPR. Multivariable logistic regression analysis showed that female gender (OR=3.175, 95% CI 1.428 to 7.059, p=0.005) and raised HbA1c (OR=1.911, 95% CI 1.066 to 3.428, p=0.03) independently predicted the occurrence of HPR. CONCLUSIONS: Despite pretreatment with aspirin and a 300 mg loading dose of clopidogrel, 21% patients undergoing PCI exhibited HPR measured by TEG. A raised level of HbA1c and female gender independently predicted the findings.

Safety and effectiveness of drug-eluting stents in Chinese patients with coronary artery disease with off- and on-label indications: results from a single-centre registry.

BACKGROUND: Off-label use of drug-eluting stents (DES) is more common than on-label use and may be associated with a persistently higher rate of adverse angiographic and clinical outcomes. OBJECTIVE: To evaluate the safety and effectiveness of unrestricted use of DES in everyday practice in a Chinese population. METHODS: Between January 2004 and May 2009, we retrospectively enrolled 1209 consecutive patients who received DES in our single centre. 84.7% of patients were treated with sirolimus-eluting stents (SES) and 15.3% of patients were treated with paclitaxel-eluting stents (PES). RESULTS: 59.0% of patients (n=713) were treated for off-label indications, with a significantly higher proportion of patients with previous coronary artery bypass grafting (CABG) (6.2% vs 0.6%, p<0.001). There were no differences in coronary risk factors. During 6-66 months' follow-up, the rate of repeat target vessel revascularisation (TVR) was significantly higher in the off-label group (14.6% vs 9.7%, p=0.011). The risk of death and myocardial infarction were not statistically different with off-label from standard use. Multivariate logistic regression showed that the independent predictors of TVR were stent type (SES vs PES, HR=0.567, 95% CI 0.395 to 0.813), previous CABG (HR=2.393, 95% CI 1.440 to 3.977), the treatment of chronic total occlusion (HR=2.786, 95% CI 1.731 to 4.484) and the treatment of left main lesion (HR=1.854, 95% CI 1.022 to 3.363). CONCLUSIONS: In our local unselected cohort of Chinese people, off-label use of DES was safe in comparison with on-label use and associated with an excellent procedural success rate, but higher TVR.